DIN EN 673-2011 Glass in building - Determination of thermal transmittance (U value) - Calculation method German version EN 673 2011《建筑物用玻璃 热透射系数(U值)的测定 计算方法 德文版本EN 673-2011》.pdf

1、April 2011 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS

2、81.040.20!$nx“1758599www.din.deDDIN EN 673Glass in building Determination of thermal transmittance (U value) Calculation methodEnglish translation of DIN EN 673:2011-04Glas im Bauwesen Bestimmung des Wrmedurchgangskoeffizienten (U-Wert) BerechnungsverfahrenEnglische bersetzung von DIN EN 673:2011-04

3、Verre dans la construction Dtermination du coefficient de transmission thermique, U Mthode de calculTraduction anglaise de DIN EN 673:2011-04SupersedesDIN EN 673:2003-06www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.2003.11 DIN EN

4、 673:2011-04 A comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee CEN/TC 129 “Glass in building” (Secretariat: NBN, Belgium). The responsible German body involved in its preparation was the Normenausschuss Bauwesen (Building and Civil Engine

5、ering Standards Committee), Working Committee NA 005-09-91 AA Prfung von Beschichtungen auf Glas. Amendments A1 and A2 were included in DIN EN 673:2003-06. Amendments This standard differs from DIN EN 673:2003-06 as follows: a) the standard has been revised in form and substance; b) the former norma

6、tive Annex A relating to the determination of the emissivitiy has been deleted, instead, reference is now made to EN 12898, Glass in building Determination of the emissivity; c) the former normative Annex B has been revised, in particular the example of iteration for a triple glazing, and is now Ann

7、ex A (normative) “Iteration procedure for glazing with more than one gas space”; d) the internal and external heat transfer coefficients have been amended to avoid any ambiguities. Previous editions DIN EN 673: 1999-01, 2001-01, 2003-06 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 673 Febr

8、uary 2011 ICS 81.040.20 Supersedes EN 673:1997English Version Glass in building Determination of thermal transmittance (U value) Calculation method Verre dans la construction Dtermination du coefficient de transmission thermique, U Mthode de calcul Glas im Bauwesen Bestimmung des Wrmedurchgangskoeff

9、izienten (U-Wert) Berechnungsverfahren This European Standard was approved by CEN on 2 January 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-

10、to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by transl

11、ation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland

12、, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMIT

13、EE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 673:2011: EEN 673:2011 (E) 2 Contents PageForeword 3Introduction .41 Scope 42 Normative references 53 Terms and

14、 definitions .54 Symbols, dimensionless numbers and subscripts 54.1 Symbols 54.2 Dimensionless Numbers .64.3 Subscripts 65 Basic formulae .75.1 General 75.2 U value 75.3 Radiation conductance hr.85.4Gas conductance hg85.4.1 General 85.4.2 Vertical glazing .95.4.3 Horizontal and angled glazing 96 Bas

15、ic material properties 96.1 Emissivity .96.2 Gas properties . 106.3 Infrared absorption of the gas . 127 External and internal heat transfer coefficients 127.1 External heat transfer coefficient he. 127.2 Internal heat transfer coefficient hi. 127.3 Design values 138 Declared values: standardized bo

16、undary conditions . 139 Expression of the results . 149.1 U values . 149.2 Intermediate values 1410 Test report . 1410.1 Information included in the test report . 1410.2 Identification of the glazing . 1410.3 Cross section of the glazing 1510.4 Results . 15Annex A (normative) Iteration procedure for

17、 glazing with more than one gas space 16Bibliography . 18DIN EN 673:2011-04 EN 673:2011 (E) 3 Foreword This document (EN 673:2011) has been prepared by Technical Committee CEN/TC 129 “Glass in building”, the secretariat of which is held by NBN. This European Standard shall be given the status of a n

18、ational standard, either by publication of an identical text or by endorsement, at the latest by August 2011, and conflicting national standards shall be withdrawn at the latest by August 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of pat

19、ent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 673:1997. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential re

20、quirements of EU Directive(s). According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Gr

21、eece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DIN EN 673:2011-04 EN 673:2011 (E) 4 Introduction CEN/TC 129/WG9 Light and energy transmission, thermal ins

22、ulation prepared a working draft based on the document ISO/DIS 10292, Thermal insulation of glazing: Calculation rules for determining the steady state U value of double or multiple glazing , document that was prepared by ISO/TC 160, Glass in building . This was published in 1997 as EN 673. This edi

23、tion is a revision of EN 673:1997. The main change in this edition is that the internal and external heat transfer coefficients have been amended slightly to avoid any ambiguities. The original annex on the determination of emissivity has been removed and reference is made to EN 12898. Other changes

24、 include the incorporation of amendments A1 and A2 to EN 673:1997 and general improvements to the text to aid understanding. 1 Scope This European Standard specifies a calculation method to determine the thermal transmittance of glazing with flat and parallel surfaces. This European Standard applies

25、 to uncoated glass (including glass with structured surfaces, e.g. patterned glass), coated glass and materials not transparent in the far infrared which is the case for soda lime glass products, borosilicate glass and glass ceramic. It applies also to multiple glazing comprising such glasses and/or

26、 materials. It does not apply to multiple glazing which include in the gas space sheets or foils that are far infrared transparent. The procedure specified in this European Standard determines the U value1) (thermal transmittance) in the central area of glazing. The edge effects due to the thermal b

27、ridge through the spacer of a sealed glazing unit or through the window frame are not included. Furthermore, energy transfer due to solar radiation is not taken into account. The effects of Georgian and other bars are excluded from the scope of this European Standard. The standard for the calculatio

28、n of the overall U value of windows, doors and shutters (see EN ISO 10077-1 1) gives normative reference to the U value calculated for the glazing components according to this standard. For the purpose of product comparison, a vertical position of the glazing is specified. In addition, U values are

29、calculated using the same procedure for other purposes, in particular for predicting: heat loss through glazing; conduction heat gains in summer; condensation on glazing surfaces; the effect of the absorbed solar radiation in determining the solar factor (see Bibliography, 2). Reference should be ma

30、de to 3, 4 and 5 or other European Standards dealing with heat loss calculations for the application of glazing U values determined by this standard. A procedure for the determination of emissivity is given in EN 12898. 1) In some countries the symbol k has been used hitherto. “” ”The rules have bee

31、n made as simple as possible consistent with accuracy. DIN EN 673:2011-04 EN 673:2011 (E) 5 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest editi

32、on of the referenced document (including any amendments) applies. EN 674, Glass in building Determination of thermal transmittance (U value) Guarded hot plate method EN 675, Glass in building Determination of thermal transmittance (U value) Heat flow meter method EN 12898, Glass in building Determin

33、ation of the emissivity 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 U value parameter of glazing which characterizes the heat transfer through the central part of the glazing, i.e. without edge effects, and states the steady-state density

34、 of heat transfer rate per temperature difference between the environmental temperatures on each side NOTE The U value is given in watts per square metre Kelvin W/(m2K). 3.2 declared value U value obtained under standardized boundary conditions (see Clause 8) 4 Symbols, dimensionless numbers and sub

35、scripts 4.1 Symbols A constant - c specific heat capacity of gas J/(kgK) d thickness of material layer (glass or alternative glazing material) m F volume fraction - h - heat transfer coefficient W/(m2K) - also thermal conductance W/(m2K) M number of material layers - n exponent - N number of spaces

36、- r thermal resistivity of glass (glazing material) mK/W P gas property - DIN EN 673:2011-04 EN 673:2011 (E) 6 s width of gas space m T absolute temperature K U thermal transmittance W/(m2K) temperature difference K corrected emissivity - nnormal emissivity (perpendicular to the surface) - gas densi

37、ty kg/m3Stefan-Boltzmanns constant 5,67 x 10-8W/(m2K4) dynamic viscosity of gas kg/(ms) - thermal conductivity of gas in space W/(mK) temperature on the Celsius scale C 4.2 Dimensionless Numbers Gr Grashof number - Nu Nuselt number - Pr Prandtl number - 4.3 Subscripts c convection e external i inter

38、nal j jthmaterial layer k kthspace g gas m mean n normal r radiation s space t total 1;2 first, second etc. DIN EN 673:2011-04 EN 673:2011 (E) 7 5 Basic formulae 5.1 General The method of this standard is based on a calculation according to the following principles. 5.2 U value The U value is given

39、by: 1U=1he+1ht+1hi(1) where heand hiare the external and internal heat transfer coefficients; htis the total thermal conductance of the glazing. 1ht=1hs1N+ dj1M rj(2) where hsis the thermal conductance of each gas space; N is the number of spaces; djis the thickness of each material layer; rjis the

40、thermal resistivity of each material (thermal resistivity of soda lime glass = 1,0 mK/W); M is the number of material layers. hs,k= hr,k+ hg,k(3) where hs,kis the heat transfer of the kthspace; hr,k is the radiation conductance; hg,kis the U value of gas. NOTE The thermal resistivity of components o

41、ther than glass (e.g. interlayers in laminated glass) may be taken into account in determining the U value. For the purpose of this standard, thermal conductivity values used for glass in building should be obtained from the table of generally accepted values in the relevant product standard (e.g. E

42、N 572-1 for basic soda lime silicate glass). In instances where the effects are not considered significant or important, a simplified approach may be taken, i.e. ignoring the effects of components other than glass. DIN EN 673:2011-04 EN 673:2011 (E) 8 5.3 Radiation conductance hrThe radiation conduc

43、tance is given by: 3km,1k,2k,1r1114 Th+= (4) where is the Stefan-Boltzmanns constant; Tm,kis the mean absolute temperature of the gas space; 1,k and 2,k are the corrected emissivities of the surfaces bounding the enclosed space between the panes at Tm,k. 5.4 Gas conductance hg 5.4.1 General The gas

44、conductance is given by: kkk,gshNu= (5) where skis the width of the kthspace; k is the thermal conductivity of the kthgas; Nu is the Nusselt number. Nu = A (Gr Pr)n(6) where A is a constant; Gr is the Grashof number; Pr is the Prandtl number; n is an exponent. Gr =9,81 s3 T 2Tm2(7) Pr =c(8) DIN EN 6

45、73:2011-04 EN 673:2011 (E) 9 where T is the temperature difference between glass surfaces bounding the gas space; is the density; is the dynamic viscosity; c is the specific heat capacity; Tmis the mean temperature. The Nusselt number is calculated from Equation (6). If Nu is less than 1, then the v

46、alue unity is used for Nu in Equation (5). 5.4.2 Vertical glazing For vertical glazing: A is 0,035 n is 0,38 5.4.3 Horizontal and angled glazing For horizontal or angled glazing and upward heat flow the heat transfer by convection is enhanced. This effect shall be considered by substituting the foll

47、owing values of A and n in Equation (6). Horizontal spaces A = 0,16 n = 0,28 Space at 45 A = 0,10 n = 0,31 For intermediate angles linear interpolation is satisfactory; however, the linear interpolation shall be between the two nearest points. When the direction of heat flow is downward the convection shall be considered suppressed for practical cases and Nu = 1 is substituted in Equation (5). 6 Basic material properties 6.1 Emissivity The corrected emissivities of the surfaces bounding the enclosed spaces are required to calculate the radiation conductance hrin Equ